1. Field of the Invention
The present invention relates to a picture display-image pickup apparatus for two-way visual communication such as a video telephone, and more particularly to a picture display-image pickup device, by which talkers can look at each other.
2. Description of the Prior Art
In a conventional visual communication system, a picture display device and an image pickup device are independent of each other. This is apparent if a television broadcasting service is taken into consideration as a concrete example. The picture display device is exemplified by a television receiver using a Braun tube for processing a video information transmitted from a television station thereby to accomplish the display only. On the other hand, the image pickup device is exemplified by a television camera, by which an image is picked up and cut at the television station so that it is transmitted to the television receiver. Thus, the television camera is used only for picking up the image. In these ways, the information flows unidirectionally from the television station using the television camera to the individuals using the television receivers. This mode has been sufficient in the case of the television broadcasting service, in which the information is broadcast from a specified transmitter to may and unspecified persons. Recently, however, information technology has advanced, and the capacity of the network of transmission lines has been increased by the use of optical cables so that the establishment of information transmitting means of not one-way but two-way type has been desired. The two-way communication has been realized and widely spread by telephones in the audio field but has never been established in the video field yet. One of causes is based upon the fact that the conventional network of transmission lines has such a small capacity that it cannot transmit far more information than the audio system. Another cause comes from that there has never been proposed such a picture display and image pickup apparatus as can allow the real two-way communication. It is needless to say that an apparatus for allowing the two-way visual communication which is called the "video telephone" has been investigated. However, the picture display and image pickup device having been used in the video telephone cannot be free from the following drawbacks.
In the video telephone, generally speaking, the picture display device and the image pickup device are arranged at a more or less spacing in a plane directing to a talker. As a result, the two talkers look at their display devices but not their pickup devices so that they never look at each other. This failure in looking at each other is a decisive drawback in case the two-way communication is to be visually accomplished. Therefore, the conventional system thus far described has almost lost the justification for its existence.